If precise dimensions are required in 3D for optimal resonance structures and gas permeability advances in this tech may play a role.
http://nextbigfuture.com/2013/09/caltech-engineers-focus-on-nano-to.html *Three-dimensional, hollow titanium nitride nanotruss with tessellated octahedral geometry. Each unit cell is on the order of 10 microns, each strut length within the unit cell is about three to five microns, the diameter of each strut is less than one micron, and the thickness of titanium nitride is roughly 75 nanometers.*
